SPARE TIRE(64A. Trunk item … or what has been put on 18-, 24-, 41- and 53-Across?), TRUST BELT (18A. Monopolist’s clothing accessory?),ICON ARTISTS (24A. Designers for Microsoft Windows?),ROUT OF THIS WORLD (41A. What Martian invaders may be intent on?) and EAT ALL COSTS (53A. What the backer of a failing business may do?) constitute the interrelated group of this durable Wednesday crossword.